To carry out research is to do systematic study of a subject — reading, measuring, checking, and writing down what you found.
It takes into or on: carry out research into sleep. There is no article and no plural, which is the trap: researches is archaic, and a research is not English at all, however natural it feels to a speaker of French, Spanish or Italian. Carry out is the standard verb here alongside do and conduct, and undertake is its more formal cousin.
1phrasecarry out researchTo do systematic study of a subject.
“They carry out research into how children sleep.”
carry out research is a piece of systematic study.
Practised in Common Word Pairs